+
+# Basic signatures of the attributes WriteMakefile takes. Each is the
+# reference type. Empty value indicate it takes a non-reference
+# scalar.
+my %Att_Sigs;
+my %Special_Sigs = (
+ C => 'ARRAY',
+ CONFIG => 'ARRAY',
+ CONFIGURE => 'CODE',
+ DIR => 'ARRAY',
+ DL_FUNCS => 'HASH',
+ DL_VARS => 'ARRAY',
+ EXCLUDE_EXT => 'ARRAY',
+ EXE_FILES => 'ARRAY',
+ FUNCLIST => 'ARRAY',
+ H => 'ARRAY',
+ IMPORTS => 'HASH',
+ INCLUDE_EXT => 'ARRAY',
+ LIBS => ['ARRAY',''],
+ MAN1PODS => 'HASH',
+ MAN3PODS => 'HASH',
+ META_ADD => 'HASH',
+ META_MERGE => 'HASH',
+ PL_FILES => 'HASH',
+ PM => 'HASH',
+ PMLIBDIRS => 'ARRAY',
+ PMLIBPARENTDIRS => 'ARRAY',
+ PREREQ_PM => 'HASH',
+ SKIP => 'ARRAY',
+ TYPEMAPS => 'ARRAY',
+ XS => 'HASH',
+ VERSION => ['version',''],
+ _KEEP_AFTER_FLUSH => '',
+
+ clean => 'HASH',
+ depend => 'HASH',
+ dist => 'HASH',
+ dynamic_lib=> 'HASH',
+ linkext => 'HASH',
+ macro => 'HASH',
+ postamble => 'HASH',
+ realclean => 'HASH',
+ test => 'HASH',
+ tool_autosplit => 'HASH',
+);
+
+@Att_Sigs{keys %Recognized_Att_Keys} = ('') x keys %Recognized_Att_Keys;
+@Att_Sigs{keys %Special_Sigs} = values %Special_Sigs;
+
+
+sub _verify_att {
+ my($att) = @_;
+
+ while( my($key, $val) = each %$att ) {
+ my $sig = $Att_Sigs{$key};
+ unless( defined $sig ) {
+ warn "WARNING: $key is not a known parameter.\n";
+ next;
+ }
+
+ my @sigs = ref $sig ? @$sig : $sig;
+ my $given = ref $val;
+ unless( grep { $given eq $_ || ($_ && eval{$val->isa($_)}) } @sigs ) {
+ my $takes = join " or ", map { _format_att($_) } @sigs;
+
+ my $has = _format_att($given);
+ warn "WARNING: $key takes a $takes not a $has.\n".
+ " Please inform the author.\n";
+ }
+ }
+}
+
+
+sub _format_att {
+ my $given = shift;
+
+ return $given eq '' ? "string/number"
+ : uc $given eq $given ? "$given reference"
+ : "$given object"
+ ;
+}
+
+
+sub prompt ($;$) { ## no critic
+ my($mess, $def) = @_;
+ Carp::confess("prompt function called without an argument")
+ unless defined $mess;
+
+ my $isa_tty = -t STDIN && (-t STDOUT || !(-f STDOUT || -c STDOUT)) ;
+